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1/*
2 * FIXME: add wdrtas_get_status and wdrtas_get_boot_status as soon as
3 * RTAS calls are available
4 */
5
6/*
7 * RTAS watchdog driver
8 *
9 * (C) Copyright IBM Corp. 2005
10 * device driver to exploit watchdog RTAS functions
11 *
12 * Authors : Utz Bacher <utz.bacher@de.ibm.com>
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2, or (at your option)
17 * any later version.
18 *
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with this program; if not, write to the Free Software
26 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
27 */
28
29#include <linux/fs.h>
30#include <linux/init.h>
31#include <linux/kernel.h>
32#include <linux/miscdevice.h>
33#include <linux/module.h>
34#include <linux/notifier.h>
35#include <linux/reboot.h>
36#include <linux/types.h>
37#include <linux/watchdog.h>
38#include <linux/uaccess.h>
39
40#include <asm/rtas.h>
41
42#define WDRTAS_MAGIC_CHAR 42
43#define WDRTAS_SUPPORTED_MASK (WDIOF_SETTIMEOUT | \
44 WDIOF_MAGICCLOSE)
45
46MODULE_AUTHOR("Utz Bacher <utz.bacher@de.ibm.com>");
47MODULE_DESCRIPTION("RTAS watchdog driver");
48MODULE_LICENSE("GPL");
49MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
50MODULE_ALIAS_MISCDEV(TEMP_MINOR);
51
52static int wdrtas_nowayout = WATCHDOG_NOWAYOUT;
53static atomic_t wdrtas_miscdev_open = ATOMIC_INIT(0);
54static char wdrtas_expect_close;
55
56static int wdrtas_interval;
57
58#define WDRTAS_THERMAL_SENSOR 3
59static int wdrtas_token_get_sensor_state;
60#define WDRTAS_SURVEILLANCE_IND 9000
61static int wdrtas_token_set_indicator;
62#define WDRTAS_SP_SPI 28
63static int wdrtas_token_get_sp;
64static int wdrtas_token_event_scan;
65
66#define WDRTAS_DEFAULT_INTERVAL 300
67
68#define WDRTAS_LOGBUFFER_LEN 128
69static char wdrtas_logbuffer[WDRTAS_LOGBUFFER_LEN];
70
71
72/*** watchdog access functions */
73
74/**
75 * wdrtas_set_interval - sets the watchdog interval
76 * @interval: new interval
77 *
78 * returns 0 on success, <0 on failures
79 *
80 * wdrtas_set_interval sets the watchdog keepalive interval by calling the
81 * RTAS function set-indicator (surveillance). The unit of interval is
82 * seconds.
83 */
84
85static int wdrtas_set_interval(int interval)
86{
87 long result;
88 static int print_msg = 10;
89
90 /* rtas uses minutes */
91 interval = (interval + 59) / 60;
92
93 result = rtas_call(wdrtas_token_set_indicator, 3, 1, NULL,
94 WDRTAS_SURVEILLANCE_IND, 0, interval);
95 if (result < 0 && print_msg) {
96 printk(KERN_ERR "wdrtas: setting the watchdog to %i "
97 "timeout failed: %li\n", interval, result);
98 print_msg--;
99 }
100
101 return result;
102}
103
104#define WDRTAS_SP_SPI_LEN 4
105
106/**
107 * wdrtas_get_interval - returns the current watchdog interval
108 * @fallback_value: value (in seconds) to use, if the RTAS call fails
109 *
110 * returns the interval
111 *
112 * wdrtas_get_interval returns the current watchdog keepalive interval
113 * as reported by the RTAS function ibm,get-system-parameter. The unit
114 * of the return value is seconds.
115 */
116static int wdrtas_get_interval(int fallback_value)
117{
118 long result;
119 char value[WDRTAS_SP_SPI_LEN];
120
121 spin_lock(&rtas_data_buf_lock);
122 memset(rtas_data_buf, 0, WDRTAS_SP_SPI_LEN);
123 result = rtas_call(wdrtas_token_get_sp, 3, 1, NULL,
124 WDRTAS_SP_SPI, __pa(rtas_data_buf),
125 WDRTAS_SP_SPI_LEN);
126
127 memcpy(value, rtas_data_buf, WDRTAS_SP_SPI_LEN);
128 spin_unlock(&rtas_data_buf_lock);
129
130 if (value[0] != 0 || value[1] != 2 || value[3] != 0 || result < 0) {
131 printk(KERN_WARNING "wdrtas: could not get sp_spi watchdog "
132 "timeout (%li). Continuing\n", result);
133 return fallback_value;
134 }
135
136 /* rtas uses minutes */
137 return ((int)value[2]) * 60;
138}
139
140/**
141 * wdrtas_timer_start - starts watchdog
142 *
143 * wdrtas_timer_start starts the watchdog by calling the RTAS function
144 * set-interval (surveillance)
145 */
146static void wdrtas_timer_start(void)
147{
148 wdrtas_set_interval(wdrtas_interval);
149}
150
151/**
152 * wdrtas_timer_stop - stops watchdog
153 *
154 * wdrtas_timer_stop stops the watchdog timer by calling the RTAS function
155 * set-interval (surveillance)
156 */
157static void wdrtas_timer_stop(void)
158{
159 wdrtas_set_interval(0);
160}
161
162/**
163 * wdrtas_log_scanned_event - logs an event we received during keepalive
164 *
165 * wdrtas_log_scanned_event prints a message to the log buffer dumping
166 * the results of the last event-scan call
167 */
168static void wdrtas_log_scanned_event(void)
169{
170 int i;
171
172 for (i = 0; i < WDRTAS_LOGBUFFER_LEN; i += 16)
173 printk(KERN_INFO "wdrtas: dumping event (line %i/%i), data = "
174 "%02x %02x %02x %02x %02x %02x %02x %02x "
175 "%02x %02x %02x %02x %02x %02x %02x %02x\n",
176 (i / 16) + 1, (WDRTAS_LOGBUFFER_LEN / 16),
177 wdrtas_logbuffer[i + 0], wdrtas_logbuffer[i + 1],
178 wdrtas_logbuffer[i + 2], wdrtas_logbuffer[i + 3],
179 wdrtas_logbuffer[i + 4], wdrtas_logbuffer[i + 5],
180 wdrtas_logbuffer[i + 6], wdrtas_logbuffer[i + 7],
181 wdrtas_logbuffer[i + 8], wdrtas_logbuffer[i + 9],
182 wdrtas_logbuffer[i + 10], wdrtas_logbuffer[i + 11],
183 wdrtas_logbuffer[i + 12], wdrtas_logbuffer[i + 13],
184 wdrtas_logbuffer[i + 14], wdrtas_logbuffer[i + 15]);
185}
186
187/**
188 * wdrtas_timer_keepalive - resets watchdog timer to keep system alive
189 *
190 * wdrtas_timer_keepalive restarts the watchdog timer by calling the
191 * RTAS function event-scan and repeats these calls as long as there are
192 * events available. All events will be dumped.
193 */
194static void wdrtas_timer_keepalive(void)
195{
196 long result;
197
198 do {
199 result = rtas_call(wdrtas_token_event_scan, 4, 1, NULL,
200 RTAS_EVENT_SCAN_ALL_EVENTS, 0,
201 (void *)__pa(wdrtas_logbuffer),
202 WDRTAS_LOGBUFFER_LEN);
203 if (result < 0)
204 printk(KERN_ERR "wdrtas: event-scan failed: %li\n",
205 result);
206 if (result == 0)
207 wdrtas_log_scanned_event();
208 } while (result == 0);
209}
210
211/**
212 * wdrtas_get_temperature - returns current temperature
213 *
214 * returns temperature or <0 on failures
215 *
216 * wdrtas_get_temperature returns the current temperature in Fahrenheit. It
217 * uses the RTAS call get-sensor-state, token 3 to do so
218 */
219static int wdrtas_get_temperature(void)
220{
221 int result;
222 int temperature = 0;
223
224 result = rtas_get_sensor(WDRTAS_THERMAL_SENSOR, 0, &temperature);
225
226 if (result < 0)
227 printk(KERN_WARNING "wdrtas: reading the thermal sensor "
228 "failed: %i\n", result);
229 else
230 temperature = ((temperature * 9) / 5) + 32; /* fahrenheit */
231
232 return temperature;
233}
234
235/**
236 * wdrtas_get_status - returns the status of the watchdog
237 *
238 * returns a bitmask of defines WDIOF_... as defined in
239 * include/linux/watchdog.h
240 */
241static int wdrtas_get_status(void)
242{
243 return 0; /* TODO */
244}
245
246/**
247 * wdrtas_get_boot_status - returns the reason for the last boot
248 *
249 * returns a bitmask of defines WDIOF_... as defined in
250 * include/linux/watchdog.h, indicating why the watchdog rebooted the system
251 */
252static int wdrtas_get_boot_status(void)
253{
254 return 0; /* TODO */
255}
256
257/*** watchdog API and operations stuff */
258
259/* wdrtas_write - called when watchdog device is written to
260 * @file: file structure
261 * @buf: user buffer with data
262 * @len: amount to data written
263 * @ppos: position in file
264 *
265 * returns the number of successfully processed characters, which is always
266 * the number of bytes passed to this function
267 *
268 * wdrtas_write processes all the data given to it and looks for the magic
269 * character 'V'. This character allows the watchdog device to be closed
270 * properly.
271 */
272static ssize_t wdrtas_write(struct file *file, const char __user *buf,
273 size_t len, loff_t *ppos)
274{
275 int i;
276 char c;
277
278 if (!len)
279 goto out;
280
281 if (!wdrtas_nowayout) {
282 wdrtas_expect_close = 0;
283 /* look for 'V' */
284 for (i = 0; i < len; i++) {
285 if (get_user(c, buf + i))
286 return -EFAULT;
287 /* allow to close device */
288 if (c == 'V')
289 wdrtas_expect_close = WDRTAS_MAGIC_CHAR;
290 }
291 }
292
293 wdrtas_timer_keepalive();
294
295out:
296 return len;
297}
298
299/**
300 * wdrtas_ioctl - ioctl function for the watchdog device
301 * @file: file structure
302 * @cmd: command for ioctl
303 * @arg: argument pointer
304 *
305 * returns 0 on success, <0 on failure
306 *
307 * wdrtas_ioctl implements the watchdog API ioctls
308 */
309
310static long wdrtas_ioctl(struct file *file, unsigned int cmd,
311 unsigned long arg)
312{
313 int __user *argp = (void __user *)arg;
314 int i;
315 static const struct watchdog_info wdinfo = {
316 .options = WDRTAS_SUPPORTED_MASK,
317 .firmware_version = 0,
318 .identity = "wdrtas",
319 };
320
321 switch (cmd) {
322 case WDIOC_GETSUPPORT:
323 if (copy_to_user(argp, &wdinfo, sizeof(wdinfo)))
324 return -EFAULT;
325 return 0;
326
327 case WDIOC_GETSTATUS:
328 i = wdrtas_get_status();
329 return put_user(i, argp);
330
331 case WDIOC_GETBOOTSTATUS:
332 i = wdrtas_get_boot_status();
333 return put_user(i, argp);
334
335 case WDIOC_GETTEMP:
336 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE)
337 return -EOPNOTSUPP;
338
339 i = wdrtas_get_temperature();
340 return put_user(i, argp);
341
342 case WDIOC_SETOPTIONS:
343 if (get_user(i, argp))
344 return -EFAULT;
345 if (i & WDIOS_DISABLECARD)
346 wdrtas_timer_stop();
347 if (i & WDIOS_ENABLECARD) {
348 wdrtas_timer_keepalive();
349 wdrtas_timer_start();
350 }
351 /* not implemented. Done by H8
352 if (i & WDIOS_TEMPPANIC) {
353 } */
354 return 0;
355
356 case WDIOC_KEEPALIVE:
357 wdrtas_timer_keepalive();
358 return 0;
359
360 case WDIOC_SETTIMEOUT:
361 if (get_user(i, argp))
362 return -EFAULT;
363
364 if (wdrtas_set_interval(i))
365 return -EINVAL;
366
367 wdrtas_timer_keepalive();
368
369 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
370 wdrtas_interval = i;
371 else
372 wdrtas_interval = wdrtas_get_interval(i);
373 /* fallthrough */
374
375 case WDIOC_GETTIMEOUT:
376 return put_user(wdrtas_interval, argp);
377
378 default:
379 return -ENOTTY;
380 }
381}
382
383/**
384 * wdrtas_open - open function of watchdog device
385 * @inode: inode structure
386 * @file: file structure
387 *
388 * returns 0 on success, -EBUSY if the file has been opened already, <0 on
389 * other failures
390 *
391 * function called when watchdog device is opened
392 */
393static int wdrtas_open(struct inode *inode, struct file *file)
394{
395 /* only open once */
396 if (atomic_inc_return(&wdrtas_miscdev_open) > 1) {
397 atomic_dec(&wdrtas_miscdev_open);
398 return -EBUSY;
399 }
400
401 wdrtas_timer_start();
402 wdrtas_timer_keepalive();
403
404 return nonseekable_open(inode, file);
405}
406
407/**
408 * wdrtas_close - close function of watchdog device
409 * @inode: inode structure
410 * @file: file structure
411 *
412 * returns 0 on success
413 *
414 * close function. Always succeeds
415 */
416static int wdrtas_close(struct inode *inode, struct file *file)
417{
418 /* only stop watchdog, if this was announced using 'V' before */
419 if (wdrtas_expect_close == WDRTAS_MAGIC_CHAR)
420 wdrtas_timer_stop();
421 else {
422 printk(KERN_WARNING "wdrtas: got unexpected close. Watchdog "
423 "not stopped.\n");
424 wdrtas_timer_keepalive();
425 }
426
427 wdrtas_expect_close = 0;
428 atomic_dec(&wdrtas_miscdev_open);
429 return 0;
430}
431
432/**
433 * wdrtas_temp_read - gives back the temperature in fahrenheit
434 * @file: file structure
435 * @buf: user buffer
436 * @count: number of bytes to be read
437 * @ppos: position in file
438 *
439 * returns always 1 or -EFAULT in case of user space copy failures, <0 on
440 * other failures
441 *
442 * wdrtas_temp_read gives the temperature to the users by copying this
443 * value as one byte into the user space buffer. The unit is Fahrenheit...
444 */
445static ssize_t wdrtas_temp_read(struct file *file, char __user *buf,
446 size_t count, loff_t *ppos)
447{
448 int temperature = 0;
449
450 temperature = wdrtas_get_temperature();
451 if (temperature < 0)
452 return temperature;
453
454 if (copy_to_user(buf, &temperature, 1))
455 return -EFAULT;
456
457 return 1;
458}
459
460/**
461 * wdrtas_temp_open - open function of temperature device
462 * @inode: inode structure
463 * @file: file structure
464 *
465 * returns 0 on success, <0 on failure
466 *
467 * function called when temperature device is opened
468 */
469static int wdrtas_temp_open(struct inode *inode, struct file *file)
470{
471 return nonseekable_open(inode, file);
472}
473
474/**
475 * wdrtas_temp_close - close function of temperature device
476 * @inode: inode structure
477 * @file: file structure
478 *
479 * returns 0 on success
480 *
481 * close function. Always succeeds
482 */
483static int wdrtas_temp_close(struct inode *inode, struct file *file)
484{
485 return 0;
486}
487
488/**
489 * wdrtas_reboot - reboot notifier function
490 * @nb: notifier block structure
491 * @code: reboot code
492 * @ptr: unused
493 *
494 * returns NOTIFY_DONE
495 *
496 * wdrtas_reboot stops the watchdog in case of a reboot
497 */
498static int wdrtas_reboot(struct notifier_block *this,
499 unsigned long code, void *ptr)
500{
501 if (code == SYS_DOWN || code == SYS_HALT)
502 wdrtas_timer_stop();
503
504 return NOTIFY_DONE;
505}
506
507/*** initialization stuff */
508
509static const struct file_operations wdrtas_fops = {
510 .owner = THIS_MODULE,
511 .llseek = no_llseek,
512 .write = wdrtas_write,
513 .unlocked_ioctl = wdrtas_ioctl,
514 .open = wdrtas_open,
515 .release = wdrtas_close,
516};
517
518static struct miscdevice wdrtas_miscdev = {
519 .minor = WATCHDOG_MINOR,
520 .name = "watchdog",
521 .fops = &wdrtas_fops,
522};
523
524static const struct file_operations wdrtas_temp_fops = {
525 .owner = THIS_MODULE,
526 .llseek = no_llseek,
527 .read = wdrtas_temp_read,
528 .open = wdrtas_temp_open,
529 .release = wdrtas_temp_close,
530};
531
532static struct miscdevice wdrtas_tempdev = {
533 .minor = TEMP_MINOR,
534 .name = "temperature",
535 .fops = &wdrtas_temp_fops,
536};
537
538static struct notifier_block wdrtas_notifier = {
539 .notifier_call = wdrtas_reboot,
540};
541
542/**
543 * wdrtas_get_tokens - reads in RTAS tokens
544 *
545 * returns 0 on success, <0 on failure
546 *
547 * wdrtas_get_tokens reads in the tokens for the RTAS calls used in
548 * this watchdog driver. It tolerates, if "get-sensor-state" and
549 * "ibm,get-system-parameter" are not available.
550 */
551static int wdrtas_get_tokens(void)
552{
553 wdrtas_token_get_sensor_state = rtas_token("get-sensor-state");
554 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) {
555 printk(KERN_WARNING "wdrtas: couldn't get token for "
556 "get-sensor-state. Trying to continue without "
557 "temperature support.\n");
558 }
559
560 wdrtas_token_get_sp = rtas_token("ibm,get-system-parameter");
561 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) {
562 printk(KERN_WARNING "wdrtas: couldn't get token for "
563 "ibm,get-system-parameter. Trying to continue with "
564 "a default timeout value of %i seconds.\n",
565 WDRTAS_DEFAULT_INTERVAL);
566 }
567
568 wdrtas_token_set_indicator = rtas_token("set-indicator");
569 if (wdrtas_token_set_indicator == RTAS_UNKNOWN_SERVICE) {
570 printk(KERN_ERR "wdrtas: couldn't get token for "
571 "set-indicator. Terminating watchdog code.\n");
572 return -EIO;
573 }
574
575 wdrtas_token_event_scan = rtas_token("event-scan");
576 if (wdrtas_token_event_scan == RTAS_UNKNOWN_SERVICE) {
577 printk(KERN_ERR "wdrtas: couldn't get token for event-scan. "
578 "Terminating watchdog code.\n");
579 return -EIO;
580 }
581
582 return 0;
583}
584
585/**
586 * wdrtas_unregister_devs - unregisters the misc dev handlers
587 *
588 * wdrtas_register_devs unregisters the watchdog and temperature watchdog
589 * misc devs
590 */
591static void wdrtas_unregister_devs(void)
592{
593 misc_deregister(&wdrtas_miscdev);
594 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE)
595 misc_deregister(&wdrtas_tempdev);
596}
597
598/**
599 * wdrtas_register_devs - registers the misc dev handlers
600 *
601 * returns 0 on success, <0 on failure
602 *
603 * wdrtas_register_devs registers the watchdog and temperature watchdog
604 * misc devs
605 */
606static int wdrtas_register_devs(void)
607{
608 int result;
609
610 result = misc_register(&wdrtas_miscdev);
611 if (result) {
612 printk(KERN_ERR "wdrtas: couldn't register watchdog misc "
613 "device. Terminating watchdog code.\n");
614 return result;
615 }
616
617 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) {
618 result = misc_register(&wdrtas_tempdev);
619 if (result) {
620 printk(KERN_WARNING "wdrtas: couldn't register "
621 "watchdog temperature misc device. Continuing "
622 "without temperature support.\n");
623 wdrtas_token_get_sensor_state = RTAS_UNKNOWN_SERVICE;
624 }
625 }
626
627 return 0;
628}
629
630/**
631 * wdrtas_init - init function of the watchdog driver
632 *
633 * returns 0 on success, <0 on failure
634 *
635 * registers the file handlers and the reboot notifier
636 */
637static int __init wdrtas_init(void)
638{
639 if (wdrtas_get_tokens())
640 return -ENODEV;
641
642 if (wdrtas_register_devs())
643 return -ENODEV;
644
645 if (register_reboot_notifier(&wdrtas_notifier)) {
646 printk(KERN_ERR "wdrtas: could not register reboot notifier. "
647 "Terminating watchdog code.\n");
648 wdrtas_unregister_devs();
649 return -ENODEV;
650 }
651
652 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
653 wdrtas_interval = WDRTAS_DEFAULT_INTERVAL;
654 else
655 wdrtas_interval = wdrtas_get_interval(WDRTAS_DEFAULT_INTERVAL);
656
657 return 0;
658}
659
660/**
661 * wdrtas_exit - exit function of the watchdog driver
662 *
663 * unregisters the file handlers and the reboot notifier
664 */
665static void __exit wdrtas_exit(void)
666{
667 if (!wdrtas_nowayout)
668 wdrtas_timer_stop();
669
670 wdrtas_unregister_devs();
671
672 unregister_reboot_notifier(&wdrtas_notifier);
673}
674
675module_init(wdrtas_init);
676module_exit(wdrtas_exit);
1/*
2 * FIXME: add wdrtas_get_status and wdrtas_get_boot_status as soon as
3 * RTAS calls are available
4 */
5
6/*
7 * RTAS watchdog driver
8 *
9 * (C) Copyright IBM Corp. 2005
10 * device driver to exploit watchdog RTAS functions
11 *
12 * Authors : Utz Bacher <utz.bacher@de.ibm.com>
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2, or (at your option)
17 * any later version.
18 *
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with this program; if not, write to the Free Software
26 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
27 */
28
29#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
30
31#include <linux/fs.h>
32#include <linux/init.h>
33#include <linux/kernel.h>
34#include <linux/miscdevice.h>
35#include <linux/module.h>
36#include <linux/notifier.h>
37#include <linux/reboot.h>
38#include <linux/types.h>
39#include <linux/watchdog.h>
40#include <linux/uaccess.h>
41
42#include <asm/rtas.h>
43
44#define WDRTAS_MAGIC_CHAR 42
45#define WDRTAS_SUPPORTED_MASK (WDIOF_SETTIMEOUT | \
46 WDIOF_MAGICCLOSE)
47
48MODULE_AUTHOR("Utz Bacher <utz.bacher@de.ibm.com>");
49MODULE_DESCRIPTION("RTAS watchdog driver");
50MODULE_LICENSE("GPL");
51
52static bool wdrtas_nowayout = WATCHDOG_NOWAYOUT;
53static atomic_t wdrtas_miscdev_open = ATOMIC_INIT(0);
54static char wdrtas_expect_close;
55
56static int wdrtas_interval;
57
58#define WDRTAS_THERMAL_SENSOR 3
59static int wdrtas_token_get_sensor_state;
60#define WDRTAS_SURVEILLANCE_IND 9000
61static int wdrtas_token_set_indicator;
62#define WDRTAS_SP_SPI 28
63static int wdrtas_token_get_sp;
64static int wdrtas_token_event_scan;
65
66#define WDRTAS_DEFAULT_INTERVAL 300
67
68#define WDRTAS_LOGBUFFER_LEN 128
69static char wdrtas_logbuffer[WDRTAS_LOGBUFFER_LEN];
70
71
72/*** watchdog access functions */
73
74/**
75 * wdrtas_set_interval - sets the watchdog interval
76 * @interval: new interval
77 *
78 * returns 0 on success, <0 on failures
79 *
80 * wdrtas_set_interval sets the watchdog keepalive interval by calling the
81 * RTAS function set-indicator (surveillance). The unit of interval is
82 * seconds.
83 */
84
85static int wdrtas_set_interval(int interval)
86{
87 long result;
88 static int print_msg = 10;
89
90 /* rtas uses minutes */
91 interval = (interval + 59) / 60;
92
93 result = rtas_call(wdrtas_token_set_indicator, 3, 1, NULL,
94 WDRTAS_SURVEILLANCE_IND, 0, interval);
95 if (result < 0 && print_msg) {
96 pr_err("setting the watchdog to %i timeout failed: %li\n",
97 interval, result);
98 print_msg--;
99 }
100
101 return result;
102}
103
104#define WDRTAS_SP_SPI_LEN 4
105
106/**
107 * wdrtas_get_interval - returns the current watchdog interval
108 * @fallback_value: value (in seconds) to use, if the RTAS call fails
109 *
110 * returns the interval
111 *
112 * wdrtas_get_interval returns the current watchdog keepalive interval
113 * as reported by the RTAS function ibm,get-system-parameter. The unit
114 * of the return value is seconds.
115 */
116static int wdrtas_get_interval(int fallback_value)
117{
118 long result;
119 char value[WDRTAS_SP_SPI_LEN];
120
121 spin_lock(&rtas_data_buf_lock);
122 memset(rtas_data_buf, 0, WDRTAS_SP_SPI_LEN);
123 result = rtas_call(wdrtas_token_get_sp, 3, 1, NULL,
124 WDRTAS_SP_SPI, __pa(rtas_data_buf),
125 WDRTAS_SP_SPI_LEN);
126
127 memcpy(value, rtas_data_buf, WDRTAS_SP_SPI_LEN);
128 spin_unlock(&rtas_data_buf_lock);
129
130 if (value[0] != 0 || value[1] != 2 || value[3] != 0 || result < 0) {
131 pr_warn("could not get sp_spi watchdog timeout (%li). Continuing\n",
132 result);
133 return fallback_value;
134 }
135
136 /* rtas uses minutes */
137 return ((int)value[2]) * 60;
138}
139
140/**
141 * wdrtas_timer_start - starts watchdog
142 *
143 * wdrtas_timer_start starts the watchdog by calling the RTAS function
144 * set-interval (surveillance)
145 */
146static void wdrtas_timer_start(void)
147{
148 wdrtas_set_interval(wdrtas_interval);
149}
150
151/**
152 * wdrtas_timer_stop - stops watchdog
153 *
154 * wdrtas_timer_stop stops the watchdog timer by calling the RTAS function
155 * set-interval (surveillance)
156 */
157static void wdrtas_timer_stop(void)
158{
159 wdrtas_set_interval(0);
160}
161
162/**
163 * wdrtas_timer_keepalive - resets watchdog timer to keep system alive
164 *
165 * wdrtas_timer_keepalive restarts the watchdog timer by calling the
166 * RTAS function event-scan and repeats these calls as long as there are
167 * events available. All events will be dumped.
168 */
169static void wdrtas_timer_keepalive(void)
170{
171 long result;
172
173 do {
174 result = rtas_call(wdrtas_token_event_scan, 4, 1, NULL,
175 RTAS_EVENT_SCAN_ALL_EVENTS, 0,
176 (void *)__pa(wdrtas_logbuffer),
177 WDRTAS_LOGBUFFER_LEN);
178 if (result < 0)
179 pr_err("event-scan failed: %li\n", result);
180 if (result == 0)
181 print_hex_dump(KERN_INFO, "dumping event, data: ",
182 DUMP_PREFIX_OFFSET, 16, 1,
183 wdrtas_logbuffer, WDRTAS_LOGBUFFER_LEN, false);
184 } while (result == 0);
185}
186
187/**
188 * wdrtas_get_temperature - returns current temperature
189 *
190 * returns temperature or <0 on failures
191 *
192 * wdrtas_get_temperature returns the current temperature in Fahrenheit. It
193 * uses the RTAS call get-sensor-state, token 3 to do so
194 */
195static int wdrtas_get_temperature(void)
196{
197 int result;
198 int temperature = 0;
199
200 result = rtas_get_sensor(WDRTAS_THERMAL_SENSOR, 0, &temperature);
201
202 if (result < 0)
203 pr_warn("reading the thermal sensor failed: %i\n", result);
204 else
205 temperature = ((temperature * 9) / 5) + 32; /* fahrenheit */
206
207 return temperature;
208}
209
210/**
211 * wdrtas_get_status - returns the status of the watchdog
212 *
213 * returns a bitmask of defines WDIOF_... as defined in
214 * include/linux/watchdog.h
215 */
216static int wdrtas_get_status(void)
217{
218 return 0; /* TODO */
219}
220
221/**
222 * wdrtas_get_boot_status - returns the reason for the last boot
223 *
224 * returns a bitmask of defines WDIOF_... as defined in
225 * include/linux/watchdog.h, indicating why the watchdog rebooted the system
226 */
227static int wdrtas_get_boot_status(void)
228{
229 return 0; /* TODO */
230}
231
232/*** watchdog API and operations stuff */
233
234/* wdrtas_write - called when watchdog device is written to
235 * @file: file structure
236 * @buf: user buffer with data
237 * @len: amount to data written
238 * @ppos: position in file
239 *
240 * returns the number of successfully processed characters, which is always
241 * the number of bytes passed to this function
242 *
243 * wdrtas_write processes all the data given to it and looks for the magic
244 * character 'V'. This character allows the watchdog device to be closed
245 * properly.
246 */
247static ssize_t wdrtas_write(struct file *file, const char __user *buf,
248 size_t len, loff_t *ppos)
249{
250 int i;
251 char c;
252
253 if (!len)
254 goto out;
255
256 if (!wdrtas_nowayout) {
257 wdrtas_expect_close = 0;
258 /* look for 'V' */
259 for (i = 0; i < len; i++) {
260 if (get_user(c, buf + i))
261 return -EFAULT;
262 /* allow to close device */
263 if (c == 'V')
264 wdrtas_expect_close = WDRTAS_MAGIC_CHAR;
265 }
266 }
267
268 wdrtas_timer_keepalive();
269
270out:
271 return len;
272}
273
274/**
275 * wdrtas_ioctl - ioctl function for the watchdog device
276 * @file: file structure
277 * @cmd: command for ioctl
278 * @arg: argument pointer
279 *
280 * returns 0 on success, <0 on failure
281 *
282 * wdrtas_ioctl implements the watchdog API ioctls
283 */
284
285static long wdrtas_ioctl(struct file *file, unsigned int cmd,
286 unsigned long arg)
287{
288 int __user *argp = (void __user *)arg;
289 int i;
290 static const struct watchdog_info wdinfo = {
291 .options = WDRTAS_SUPPORTED_MASK,
292 .firmware_version = 0,
293 .identity = "wdrtas",
294 };
295
296 switch (cmd) {
297 case WDIOC_GETSUPPORT:
298 if (copy_to_user(argp, &wdinfo, sizeof(wdinfo)))
299 return -EFAULT;
300 return 0;
301
302 case WDIOC_GETSTATUS:
303 i = wdrtas_get_status();
304 return put_user(i, argp);
305
306 case WDIOC_GETBOOTSTATUS:
307 i = wdrtas_get_boot_status();
308 return put_user(i, argp);
309
310 case WDIOC_GETTEMP:
311 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE)
312 return -EOPNOTSUPP;
313
314 i = wdrtas_get_temperature();
315 return put_user(i, argp);
316
317 case WDIOC_SETOPTIONS:
318 if (get_user(i, argp))
319 return -EFAULT;
320 if (i & WDIOS_DISABLECARD)
321 wdrtas_timer_stop();
322 if (i & WDIOS_ENABLECARD) {
323 wdrtas_timer_keepalive();
324 wdrtas_timer_start();
325 }
326 /* not implemented. Done by H8
327 if (i & WDIOS_TEMPPANIC) {
328 } */
329 return 0;
330
331 case WDIOC_KEEPALIVE:
332 wdrtas_timer_keepalive();
333 return 0;
334
335 case WDIOC_SETTIMEOUT:
336 if (get_user(i, argp))
337 return -EFAULT;
338
339 if (wdrtas_set_interval(i))
340 return -EINVAL;
341
342 wdrtas_timer_keepalive();
343
344 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
345 wdrtas_interval = i;
346 else
347 wdrtas_interval = wdrtas_get_interval(i);
348 /* fallthrough */
349
350 case WDIOC_GETTIMEOUT:
351 return put_user(wdrtas_interval, argp);
352
353 default:
354 return -ENOTTY;
355 }
356}
357
358/**
359 * wdrtas_open - open function of watchdog device
360 * @inode: inode structure
361 * @file: file structure
362 *
363 * returns 0 on success, -EBUSY if the file has been opened already, <0 on
364 * other failures
365 *
366 * function called when watchdog device is opened
367 */
368static int wdrtas_open(struct inode *inode, struct file *file)
369{
370 /* only open once */
371 if (atomic_inc_return(&wdrtas_miscdev_open) > 1) {
372 atomic_dec(&wdrtas_miscdev_open);
373 return -EBUSY;
374 }
375
376 wdrtas_timer_start();
377 wdrtas_timer_keepalive();
378
379 return nonseekable_open(inode, file);
380}
381
382/**
383 * wdrtas_close - close function of watchdog device
384 * @inode: inode structure
385 * @file: file structure
386 *
387 * returns 0 on success
388 *
389 * close function. Always succeeds
390 */
391static int wdrtas_close(struct inode *inode, struct file *file)
392{
393 /* only stop watchdog, if this was announced using 'V' before */
394 if (wdrtas_expect_close == WDRTAS_MAGIC_CHAR)
395 wdrtas_timer_stop();
396 else {
397 pr_warn("got unexpected close. Watchdog not stopped.\n");
398 wdrtas_timer_keepalive();
399 }
400
401 wdrtas_expect_close = 0;
402 atomic_dec(&wdrtas_miscdev_open);
403 return 0;
404}
405
406/**
407 * wdrtas_temp_read - gives back the temperature in fahrenheit
408 * @file: file structure
409 * @buf: user buffer
410 * @count: number of bytes to be read
411 * @ppos: position in file
412 *
413 * returns always 1 or -EFAULT in case of user space copy failures, <0 on
414 * other failures
415 *
416 * wdrtas_temp_read gives the temperature to the users by copying this
417 * value as one byte into the user space buffer. The unit is Fahrenheit...
418 */
419static ssize_t wdrtas_temp_read(struct file *file, char __user *buf,
420 size_t count, loff_t *ppos)
421{
422 int temperature = 0;
423
424 temperature = wdrtas_get_temperature();
425 if (temperature < 0)
426 return temperature;
427
428 if (copy_to_user(buf, &temperature, 1))
429 return -EFAULT;
430
431 return 1;
432}
433
434/**
435 * wdrtas_temp_open - open function of temperature device
436 * @inode: inode structure
437 * @file: file structure
438 *
439 * returns 0 on success, <0 on failure
440 *
441 * function called when temperature device is opened
442 */
443static int wdrtas_temp_open(struct inode *inode, struct file *file)
444{
445 return nonseekable_open(inode, file);
446}
447
448/**
449 * wdrtas_temp_close - close function of temperature device
450 * @inode: inode structure
451 * @file: file structure
452 *
453 * returns 0 on success
454 *
455 * close function. Always succeeds
456 */
457static int wdrtas_temp_close(struct inode *inode, struct file *file)
458{
459 return 0;
460}
461
462/**
463 * wdrtas_reboot - reboot notifier function
464 * @nb: notifier block structure
465 * @code: reboot code
466 * @ptr: unused
467 *
468 * returns NOTIFY_DONE
469 *
470 * wdrtas_reboot stops the watchdog in case of a reboot
471 */
472static int wdrtas_reboot(struct notifier_block *this,
473 unsigned long code, void *ptr)
474{
475 if (code == SYS_DOWN || code == SYS_HALT)
476 wdrtas_timer_stop();
477
478 return NOTIFY_DONE;
479}
480
481/*** initialization stuff */
482
483static const struct file_operations wdrtas_fops = {
484 .owner = THIS_MODULE,
485 .llseek = no_llseek,
486 .write = wdrtas_write,
487 .unlocked_ioctl = wdrtas_ioctl,
488 .open = wdrtas_open,
489 .release = wdrtas_close,
490};
491
492static struct miscdevice wdrtas_miscdev = {
493 .minor = WATCHDOG_MINOR,
494 .name = "watchdog",
495 .fops = &wdrtas_fops,
496};
497
498static const struct file_operations wdrtas_temp_fops = {
499 .owner = THIS_MODULE,
500 .llseek = no_llseek,
501 .read = wdrtas_temp_read,
502 .open = wdrtas_temp_open,
503 .release = wdrtas_temp_close,
504};
505
506static struct miscdevice wdrtas_tempdev = {
507 .minor = TEMP_MINOR,
508 .name = "temperature",
509 .fops = &wdrtas_temp_fops,
510};
511
512static struct notifier_block wdrtas_notifier = {
513 .notifier_call = wdrtas_reboot,
514};
515
516/**
517 * wdrtas_get_tokens - reads in RTAS tokens
518 *
519 * returns 0 on success, <0 on failure
520 *
521 * wdrtas_get_tokens reads in the tokens for the RTAS calls used in
522 * this watchdog driver. It tolerates, if "get-sensor-state" and
523 * "ibm,get-system-parameter" are not available.
524 */
525static int wdrtas_get_tokens(void)
526{
527 wdrtas_token_get_sensor_state = rtas_token("get-sensor-state");
528 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) {
529 pr_warn("couldn't get token for get-sensor-state. Trying to continue without temperature support.\n");
530 }
531
532 wdrtas_token_get_sp = rtas_token("ibm,get-system-parameter");
533 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) {
534 pr_warn("couldn't get token for ibm,get-system-parameter. Trying to continue with a default timeout value of %i seconds.\n",
535 WDRTAS_DEFAULT_INTERVAL);
536 }
537
538 wdrtas_token_set_indicator = rtas_token("set-indicator");
539 if (wdrtas_token_set_indicator == RTAS_UNKNOWN_SERVICE) {
540 pr_err("couldn't get token for set-indicator. Terminating watchdog code.\n");
541 return -EIO;
542 }
543
544 wdrtas_token_event_scan = rtas_token("event-scan");
545 if (wdrtas_token_event_scan == RTAS_UNKNOWN_SERVICE) {
546 pr_err("couldn't get token for event-scan. Terminating watchdog code.\n");
547 return -EIO;
548 }
549
550 return 0;
551}
552
553/**
554 * wdrtas_unregister_devs - unregisters the misc dev handlers
555 *
556 * wdrtas_register_devs unregisters the watchdog and temperature watchdog
557 * misc devs
558 */
559static void wdrtas_unregister_devs(void)
560{
561 misc_deregister(&wdrtas_miscdev);
562 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE)
563 misc_deregister(&wdrtas_tempdev);
564}
565
566/**
567 * wdrtas_register_devs - registers the misc dev handlers
568 *
569 * returns 0 on success, <0 on failure
570 *
571 * wdrtas_register_devs registers the watchdog and temperature watchdog
572 * misc devs
573 */
574static int wdrtas_register_devs(void)
575{
576 int result;
577
578 result = misc_register(&wdrtas_miscdev);
579 if (result) {
580 pr_err("couldn't register watchdog misc device. Terminating watchdog code.\n");
581 return result;
582 }
583
584 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) {
585 result = misc_register(&wdrtas_tempdev);
586 if (result) {
587 pr_warn("couldn't register watchdog temperature misc device. Continuing without temperature support.\n");
588 wdrtas_token_get_sensor_state = RTAS_UNKNOWN_SERVICE;
589 }
590 }
591
592 return 0;
593}
594
595/**
596 * wdrtas_init - init function of the watchdog driver
597 *
598 * returns 0 on success, <0 on failure
599 *
600 * registers the file handlers and the reboot notifier
601 */
602static int __init wdrtas_init(void)
603{
604 if (wdrtas_get_tokens())
605 return -ENODEV;
606
607 if (wdrtas_register_devs())
608 return -ENODEV;
609
610 if (register_reboot_notifier(&wdrtas_notifier)) {
611 pr_err("could not register reboot notifier. Terminating watchdog code.\n");
612 wdrtas_unregister_devs();
613 return -ENODEV;
614 }
615
616 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
617 wdrtas_interval = WDRTAS_DEFAULT_INTERVAL;
618 else
619 wdrtas_interval = wdrtas_get_interval(WDRTAS_DEFAULT_INTERVAL);
620
621 return 0;
622}
623
624/**
625 * wdrtas_exit - exit function of the watchdog driver
626 *
627 * unregisters the file handlers and the reboot notifier
628 */
629static void __exit wdrtas_exit(void)
630{
631 if (!wdrtas_nowayout)
632 wdrtas_timer_stop();
633
634 wdrtas_unregister_devs();
635
636 unregister_reboot_notifier(&wdrtas_notifier);
637}
638
639module_init(wdrtas_init);
640module_exit(wdrtas_exit);